6861 has 4 divisors (see below), whose sum is σ = 9152. Its totient is φ = 4572.

The previous prime is 6857. The next prime is 6863. The reversal of 6861 is 1686.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 6861 - 2² = 6857 is a prime.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6863) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1141 + ... + 1146.

It is an arithmetic number, because the mean of its divisors is an integer number (2288).

2⁶⁸⁶¹ is an apocalyptic number.

It is an amenable number.

6861 is a deficient number, since it is larger than the sum of its proper divisors (2291).

6861 is a wasteful number, since it uses less digits than its factorization.

6861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2290.

The product of its digits is 288, while the sum is 21.

The square root of 6861 is about 82.8311535595. The cubic root of 6861 is about 19.0018465426.

The spelling of 6861 in words is "six thousand, eight hundred sixty-one".